The distribution and nature of star dunes: A global analysis

Abstract Star dunes, which occur on Mars and Titan and are also evident in Earth’s stratigraphic record, are widespread in the world’s drylands and 25 provinces have been identified and characterised based on an analysis of Google Earth images. They occur in East Asia, Western Asia, the Americas, southern Africa and northern Africa. Star dunes are absent in inland Australian, Kalahari and Indian sand seas and in the southern Sahara. Morphometric measurements across a wide range of sites reveal star dune densities of 7 to 81 per 100 km2 (mean 30 per km2), dune widths of 125–3071 m (mean 895 m) and heights of 4–291 m (mean 75 m). Star dunes have a great diversity of forms, which include simple pyramids, complex features, checkerboard patterns, symmetrical and asymmetrical forms, stars along linear dunes and stars along transverse dunes. In some areas star dunes show an association with mega-domes. In this paper they are classified into 10 types, though it is clear that some dunes may show characteristics of more than one type. Star dunes develop in areas with low rainfall, variable wind directions and in association with topographic barriers. They are a more widespread and varied phenomenon than has previously been recognised.